Windows Phones increasing in price on eBay. A new trend?

Here's some interesting statistics that jive nicely with that earlier Australian report on the HTC Mozart. At least on eBay in the UK demand, as measured by increasing prices, has been on the upswing for the last few weeks for certain Windows Phone models, specifically the HTC Mozart, Dell Venue Pro and HTC 7 Pro--basically the creme of the crop, if you ask us.

The measurements, as graphed above, show a steadily increase in price since early September, just when Mango-fever was picking up. The jump in price is also fairly significant, with the 7 Pro going from an average of £240 to £350 in just 30 days.

Sure, it could be coincidence and perhaps other factors are at play here, but to our eyes, this is starting to look like a trend. We should note though, not all Windows Phone are benefiting from the "Mango bump" as the HTC HD7, Samsung Omnia 7 and and HTC Trophy are all down. Thoughts?

Update: WPCentral reader Oli S. lets us know the same trend shows on Amazon.de too, with the HD7 increasing from330 € to over 400 € now and staying steady.